Tom is a 40 year old diabetic man who reports 2 months of brown patch under his armpits, it is mildly itchy.

Direct Examination looks like:

Woods Lamp inspection looks like:

Cause of erythrasma

• Corynebacterium minutissimum

Diagnosis of erythrasma

• Woods lamp
• Skin scrapings for MCS

Treatment of erythrasma

• Fusidic acid cream topically
• Clindamycin solution topically
• Whitfield ointment topically
• Oral erythromycoin
• Oral tetracycline
• Photodynamic therapy

Further Reading

• https://www.dermnetnz.org/topics/erythrasma/
• https://www.racgp.org.au/afp/2012/october/interdigital-erosions/
• https://www.uptodate.com/contents/erythrasma